Fluid dynamic bearings are utilized in motors used for computer hard drives, and fluid dynamic bearings are designed to provide stiffness to the motors in which they are used. Such bearings use a fluid medium between two of the bearing surfaces to provide stiffness. In operation, a groove-bearing surface of a fluid dynamic bearing pumps the fluid medium as a response to the relative motion between two bearing surfaces, and, consequently pressurizes the bearing, providing stiffness.
In a journal bearing, radial motion and angular motion are resisted by the bearing as a result of the stiffness provided. In a thrust bearing, axial and angular motion are resisted as a result of the stiffness provided. In either case, a groove-bearing surface and bearing gap (the offset between bearing surfaces) may be adjusted for stiffness. As such, different groove configurations may be used in different bearing designs.